Gramet doesn’t forecast cloud reliably – especially not low and mid level cloud.
The MSLP chart suggests no serious convective activity:
Isn’t EDMA quite close to EDDM?
EDDM 021700Z 0218/0324 25007KT 9999 FEW010 BKN030 PROB30 TEMPO 0218/0221 29015G25KT 1200 SHSN BKN007CB TEMPO 0300/0309 2000 BCFG BECMG 0303/0306 VRB03KT PROB30 TEMPO 0303/0308 0500 FZFG VV002 BECMG 0308/0310 07005KT
So, purely in terms of cloudbase, they are forecasting FEW010 BKN030 for 1200Z on the 3rd.
Yes EDDM is close but the wx is not similar. They seem to have low vis and fog more often. At least thats what I have seen.
If someone else has more local experience Id love to hear from you.
Too bad about Gramet it looks very pretty. How is it for forecasting ice?
Well, not all of us are so negative about Gramet. I for one think it is a fantastic new tool that has somewhat transformed my weather briefings and boosted my confidence departing in less than ideal conditions.
It sometimes misses minor layers of clouds in the lower levels, but anything of real sigificance for the IFR flyer is usually predicted rather precisely. I have had occasions where the Gramet was totally spot on, both in terms of cloud cover as well as ceilings and cloud tops.
That said, it’s only ever one tool in the toolbox.
Re ice forecasting it is as good or as bad as all the other tools. It does not really forecast ice. What it does is it forecasts cloud and it forecasts temperatures, and where the two come together, it forecasts ice. Not really a huge effort. On the other hand, it is my experience that where clouds and temps between 0 and -15 degrees fall together, there is always some nice. So, after all, it’s not a bad approach.
It does not really forecast ice. What it does is it forecasts cloud and it forecasts temperatures, and where the two come together, it forecasts ice. Not really a huge effort.
It’s a bit more sophisticated than that. Here’s a description of the icing algorithm.
I know, in theory it is more complex, but in practice it comes out to what I said. It’s just the severity of ice that changes.
I would not say I am negative about GRAMET – either the OGIMET one or Achim’s one.
It is just very hard to forecast such detail. And if you say 50nm is too far apart for accuracy, no weather model is going to be any good this far ahead.
GRAMET is a good tool for the toolbox, and the forecasts are always used in the context of the aircraft one is flying. If you want wx for growing tomatoes you want to forecast the cloud cover and you don’t care if the cloudbase is 1000ft or FL600. If you are flying say a TB20 and the forecast is SCT030 and there isn’t any convective wx then the tops might be 6000ft and then you look at the 0C level (which is normally fairly well forecast) to see if you can climb through. That decision will be reviewed just before the flight, obviously.
I would look at the GRAMET and if it forecasts tops at FL150 enroute and the departure and arrival areas look VMC-flyable (holes are OK) then I would go. The IR image will confirm it just before the flight and that isn’t accurate anyway (plus or minus say 3000ft) but is good enough again in the context of the aircraft capability.
Low level cloud especially is almost impossible to forecast, and fog / very low vis tends to be hopeless until hours before by which time it becomes pretty obvious. Also the time of fog clearance is hopelessly badly forecast.
I was referring to the TAF that it drops off for EDMA some time today I think 9PM local. Ill ck again.
It would be nice to have a forecast for tomorrow early afternoon. If not, than at least for the morning.
I;ll report back with how the conditions were and how accurate the wx forecast was.
Not sure I understand but there isn’t a TAF generated for an airport which is closed. Except some which extend past closing time (fairly common), and automated TAFs which can appear anytime (rare… I think France does some but they are locally regarded as a bit of a game).
The forecasters in Europe generate the TAF from a combination of (a) the METAR and (b) from their 3D model which is commercially secret. And hopefully local knowledge.
I have never known anybody who was able to do any better than use the professionally / locally produced data (tafs and metars) and when these are not available, use GFS-derived stuff, and the few nationally produced longer range charts like e.g. the UK MSLPs.
That’s why I think learning about Met is equivalent to saying one can out-forecast those who do it for a living, which is a bit like saying that insurance companies lose money 
Ok have never run into the airport is closed so we wont give it any weather guidance.
Im leaving on the flt in a few mins. to go to the airport. The wx looks good VFR all the way but still filed IFR. I like the feeling big brother is watching over me.
At least in this case.
It’s a bit more sophisticated than that. Here’s a description of the icing algorithm.
The description talks in part about icing over mountainous terrain and contains the following advice:
The magenta flight path stays above the icing but it is still a concern because the icing could reach higher and in case of a forced landing, the terrain is forecast to be overcast and in icing. This is a situation where you might want to have two engines or a ballistic airframe parachute.
One criticism that is frequently levelled at BRS equipped pilots is that they use the system as a reason to take on risks like this and, whilst I understand that having a second engine might make that option viable, IMHO a BRS doesn’t and, as a pilot of such an aircraft myself, I wouldn’t knowingly take that risk.
